Gear set



P'. C. DAY

- GEAR SET May 20, 1930.

Filed Aug. 6, 1927 2 Sheets-Shee I N VEN TOR. EH52 C Z2422 A TTORNE Y.

P. c. DAY

GEAR SET May 20,1930.

Filed Aug. 6, 1927 2 Sheets-Sheet I N V EN TOR. F 55;? 5 D1121.

A TTORNE Y.

I entire set.

Patented May 20, 1 930 UNITED STATES PATENT OFFICE PERCY 0. DAY, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE FALK CORPORATION, OF MILWAUKEE, WISCONSIN, A. CORPORATION OF v'WISCON'SIH' GEAR SET Application filed August 6, 1927. Serial No. 211,064.

This invention relates to heavy duty gear sets for converting rotary motion at relatively high speed and low torque into rotary motion at relatively low speed and high torque or vice versa.

The general aim of the present invention.

is the provision of a gear set for the purposes named of improved economical design. This I have accomplished by the use of separate gear trains so constructed and combined with the driving and driven parts that each carries a predetermined fractional part of the entire transmitted load. The marked reduction in the size and weight of the com onent parts of each gear train, made ossible y this ractional transmission of the oad, results in a material reduction in the total cost of the Attempts heretofore made to use separate gear trains for carrying fractional parts of the load have not proven entirely successful due to an inability to effect a proper distribution of the load in a satisfactory manner. This problem of proper distribution is rendered difficult by reason of the positive nature of each ear train and the inherent back lash and minute inequalities therein which cause one train to assume, atlleast momentarily, the entire load to the exclusion of the other. The introduction of a resilient medium in an effort to equalize the load upon the separate gear trains only leads to further difiiculties. A more specific object of the present invention is the provision in a gear set of the character mentioned of a novel combination and arrangement of parts by which each of the separate gear trains will at all times carry its allotted portion of the load Without destroying the positive nature of the drive. a

' Other objects and advantages will appea from the following description of an illustrative embodiment of the present invention.

In the drawings Figure 1 is a plan view of a gear set constructed in accordance with the present invention, with the top half of the gear casing removed.

Fig. 2 is a vertical sectional view on the line 22 of Figure 1.

Fig. 3 is a vertical sectional view on the line 3-3 of Figure 1.

The gear set selected for illustration provides for a triple reduction in speed between the drive shaft 10 and driven shaft 11. The drive shaft 10 in this instance is 'ournaled in appropriate spaced bearings 12 ormed in the upper half 13 of a horizontally split casing Whose lower portion 14 is formed with an appropriate base 15 and with appropriate rigid supports 16 for the bearings of the several shafts. Aherring-bone pinion 17, disosed between the bearings 12, is formed integral with the drive shaft and meshes with a herring-bone gear 18, keyed or otherwise fixed to a shaft 19, journaled in spaced bearings 20. Shaft 10 is mounted for limited end play within the bearings 12, in order to permit the pinion 17 toadjust itself to the gear 18, and shaft 19 is mounted for limited end play within the bearings 20 for a purpose which will hereinafter appear.

One end 21 of the shaft 19 projects beyond the bearings 20 and carries two single helical pinions 22 and 23 the spiral angle of each being equal to but the reverse of the other. Two single helical 1gears 24 and 25, disposed at opposite sides 0 the shaft 19, mesh with pinions 22 and 23, respectively. Gear 24 is rin 30, anchored on the shaft and coac ting.

wit the end of one bearing to retain the shaft against movement toward the right, and a take-up plate 31 clamped upon the end of the shaft and coacting with the end of the otherbearing to retain the shaft against movement toward the left. (See F ig. 3.) A single helical pinion 32 formed on shaft 26, inter-' mediate the bearings 27, meshes with a single helical gear 33, keyed or otherwise fixed to the driven shaft 1.1, and a similar pinion 34 on shaft 28 also meshes with gear 33 at the opposite side thereof. Shaft 11 is journaled in a pair of spaced bearings 35 and is re tained against end play by appropriate means ,It willbe noted that, by virtue of the'freverse spiral angle on the two pinions 22 and 23, the and ear lengt pressure between the will tend to shift the s aft 19 in the op tooth pressure between the pinion 22 24 willtend to shift the shaftwl9 inion 23 and gear in its bearings 20 it will always assume a position in'which theend thrusts f roduced b these reactions are balanced,'so't at the toot ressures between pinion 22 and gear 24 and etween inion 23 and gear 25 are alwags equal an the load transmitted through t e shaft 19 is equally divided be een the two gear trains 22, 24, 32 and 33, and 23, 25, 34 and 33, respectively, It willalso be noted that since t e tooth pressures between pinion 22 and gear 24 and between pinion 23 and gear 25 are equal butin opposite directions the transverse thrustsupon the end 21 of the shaft 19jisbalanced, and there is therefore no need of a third bearing to support the projecting end of this shaft; It will be further noted that the tooth ressures on the pinion 34 are much greater t n the tooth pressures on the ar 25 because of the difference in distance 0 these teeth from the axis of the shaft 28, so that the tooth pressure upon the pinion pinions on and secon 34 is suflicient at all times to retain the shaft 28 against tilting in its bearings 28 under the influenceiof the transverse thrust of the gear 25 thereon.- Due to this peculiarreaction it has beenafound unnecessary to provide a for the projected end of the third bearing shaft 28. 1 The same is true of shaft 26. This elimination of a third bearing for shafts 19, 26 and 28 means a marked reduction in the cost of the gear set.

Various changes may be made in the embodiment'of the invention hereinabove specifically described without departing from or sacrificing the advantages of the invention as defined in the appended claim.

.I claim In a gear set the combination of a shaft,'a

pinion thereon, a second shaft, a pair of spaced bearings therefor permitting axial movement thereof, a gear on sand second shaft between saidbearingsand meshing with said pinion, a air of single'helical shaft beyond said bearings a third shaft coaxial with said second shaft, a gear on said third shaft, a pair of shafts, a pair of spaced bearings for each a of said pair ofshafts a pinion on each of said pair of shafts between the bearings thereof and-meshin -with said'last named gear, means for hol 'ng said pair of shafts against end movement, and a single helical gear on each of said pair of shafts beyond the wise in one direction and the tooth.

1,75e,eae

bearin thereof and meshing with one of said single ehcal gears, said single helical gears being axially movable with said second shaft and coacting with said single helical gears to osite T difection. Since this shaft is freely shi table free 

